bonding, structure and the properties of matter Flashcards
explain the properties of ionic compounds in relation to structure and bonding
high melting points
- because there is a strong electrostatic attraction between ions which needs a lot of energy to overcome
do not conduct unless molten or aqueous
- when molten or aqueous the ions are free to move around and carry a charge
explain the properties of small covalent compounds in relation to structure and bonding
gases at room temperature
- because they have strong covalent bonds but have weak intermolecular forces which need over little energy to overcome ( room temperature is enough )
do not conduct
- because they have no overall charge and no free electrons
explain the properties of graphite compounds in relation to structure and bonding
conducts electricity
- because only three of carbon’s four outer electrons are involved in bonding the delocalised electrons can carry a charge
soft / spillery
- because the layers ( graphene ) are separated with weak intermolecular forces ( easy to break )
explain the properties of diamond / silicon dioxide in relation to structure and bonding
really hard
- because it is in a giant lattice structure with strong covalent bonds between the
carbon atoms
does not conduct electricity
- because all the electrons are involved in bonding so there are no free electrons that can carry a charge
high melting point
- because the strong intermolecular forces require a lot of energy to break
explain the properties of graphene in relation to structure and bonding
conducts electricity
- each carbon / atom forms 3 (covalent) bonds
one electron per carbon / atom is delocalised
(so) these electrons carry charge through the graphite or
- each carbon atom forms three covalent bonds, creating sheets of carbons atoms arranged in hexagons
soft and slippery
- because the layers are only held together weakly not strong covalent bonds so the layers are free to move over each other
high melting point
- because the covalent bonds within the layers take a lot of energy to break
what size are nano-particles?
<1000nm
why are nano-particles good?
- because they have a high SA:V so less is needed compared to other materials
what are some uses for nano-particles?
medicine
- medicine can be stored in nano-particle capsules which can be guided by a magnet to the right place
explain why graphite conducts electricity ( in relation to structure and bonding
each carbon / atom forms 3 (covalent) bonds
one electron per carbon / atom is delocalised
(so) these electrons carry charge through the graphite or
why is hydrogen chloride a gas a room temperature?
because it is composed of small molecules
which have weak intermolecular forces
which take little energy to overcome
metal chlorides are usually - ionic or covalent - compounds
ionic
what are the properties of ionic compounds?
they are usually solids room temperature
high melting and boiling points
don’t conduct electricity unless they are molten or aqueous
why does iodine have a higher boiling point than chlorine
because the forces between iodine molecules are stronger
explain how a covalent bond holds two atoms together
electrostatic force of attraction between shared pair of negatively charged electrons
and both positively charged nuclei
why are metals malleable?
because they are composed of regular layers of atoms that can slide over each other
